1. Field of the Invention
This invention relates generally to rolling mill oil film bearings, and is concerned in particular with an improved neck seal employed to retain oil in and to exclude contaminants from such bearings.
2. Description of the Prior Art
With reference initially to FIG. 1, a known oil film bearing assembly is partially shown as comprising a roll 10 having an end face 12, and a tapered neck section 14 leading to a reduced diameter end section 16 surrounded by a sleeve 18. The sleeve is keyed or otherwise fixed to the roll neck for rotation therewith within a bushing 20 fixed in a chock 22.
A flexible neck seal 24 is received on the tapered neck section 14 for rotation therewith. The seal has a circular body with inboard and outboard lips 26, 28 in contact with the neck surface. The outboard lip 28 is reinforced by a spring , and is separated from the seal body by a gap 30. First and second axially spaced flanges 32, 34 project radially outwardly from the seal body, and a third flinger 36 projects angularly towards the chock 22.
The seal body is internally reinforced by an embedded steel cable 38 and coiled spring 40, and is externally constrained by a metal retaining band 42 located between the flanges 32, 34.
The flanges 32, 34 have oppositely directed lips arranged to frictionally contact the shoulders of a seal end plate 44, the latter being fixed to the chock 22 and cooperating therewith to define a sump 46. An inner seal ring 48 and a water guard 50 complete the seal assembly.
In operation, the roll 10, neck seal 24, inner seal ring 48 and sleeve 18 rotate together, while the bushing 20, chock 22, seal end plate 44 and water guard 50 remain stationary. Oil is supplied continuously between the sleeve 18 and bushing 20. The thus supplied oil is hydrodynamically formed into a film at the bearing load zone before emerging from between the sleeve and bushing for collection in the sump 46.
The lip seal 28, flinger 36 and outboard flange 34 serve to retain oil in the bearing, whereas the water guard 50, inner seal ring 48 and inboard flange 32 serve to exclude cooling water and entrained contaminants from penetrating into the bearing.
Proper seating and positioning of the neck seal 24 on the tapered roll neck section 14 is critical to the avoidance of leakage problems. However, because of the gap 30, the outboard portion of the seal body under the outboard flange 34 lacks radial support, with the main contact between the seal body and the roll neck being at 52 under the inboard flange 32. Thus, when the seal is mounted on the roll neck, friction at 54 between the end of the sleeve 20 and the unsupported portion of the seal body can cause the seal to seat in an offset position. The mispositioning is random, virtually impossible to detect, and can cause leakage.
The objective of the present invention is to eliminate or at least significantly minimize the above described problem by providing additional and strategically positioned radial support for the seal body, and by preferably coupling this additional support with a reduction in friction between the end of the sleeve and the seal body.
In accordance with the present invention, the seal body is provided with axially spaced support ridges projecting inwardly into the seal bore for contact with the roll neck. The support ridges are respectively aligned radially with solid portions of the seal body and with the seal flanges and the outer metal retaining band, thus providing support and position control for these critical components, while also minimizing frictional resistance to axial movement of the seal body into its seated position on the tapered section of the roll neck.
Advantageously, additional compliance ridges are added to the seal body at its interface with the end of the sleeve. The compliance ridges are deformable to ease radial positioning of the seal body.
These and other features and advantages of the present invention will now be described in greater detail with continued reference to the accompanying drawings, wherein: